Methods and mechanisms for maintaining an electro-active polymer in a pre-stretch state and uses thereof

ABSTRACT

In some embodiments, the present invention is directed to an actuator which includes at least the following: a pre-stretched electro-active polymer film being pre-stretched in a single or biaxial planar directions; at least one first semi-stiff conductor attached to a first surface of the pre-stretched electro-active polymer film, wherein the first surface is parallel to the single or biaxial planar stretch directions; at least one second semi-stiff conductor attached to a second surface of the pre-stretched electro-active polymer film, wherein the second surface is opposite to the first surface; where the semi-stiff conductors are configured to: fix the pre-stretched electro-active polymer film in a pre-stretched state and allow the pre-stretched electro-active polymer film to expand; a pair of mechanical connectors coupled to each end of an active region of the pre-stretched electro-active polymer film.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/982,645; filed Dec. 29, 2015; entitled “METHODS AND MECHANISMS FORMAINTAINING AN ELECTRO-ACTIVE POLYMER IN A PRE-STRETCH STATE AND USESTHEREOF”, which claims the priority of U.S. provisional patentapplication No. 62/097,372; filed Dec. 29, 2014; entitled “METHODS ANDMECHANISMS FOR MAINTAINING AN ELECTRO-ACTIVE POLYMER IN A PRE-STRETCHSTATE,” U.S. Provisional Application No. 62/112,498; filed Feb. 5, 2015;entitled “METHODS AND MECHANISMS FOR MAINTAINING AN ELECTRO-ACTIVEPOLYMER FILM IN A PRE-STRETCH STATE BY WRAPPING IT AROUND A SOLID BODY,”and U.S. Provisional Application No. 62/112,509; filed Feb. 5, 2015;entitled “ELECTRO-ACTIVE POLYMER BASED COMPRESSION BANDAGE,” which areincorporated herein by reference in their entirety for all purposes.

TECHNICAL FIELD

In some embodiments, the present invention relates to methods andmechanisms thereof for maintaining electro-active polymers film in apre-stretch state.

BACKGROUND

Typically, electro-active polymers are polymers that exhibit a change insize or shape when stimulated by an electric field.

BRIEF SUMMARY

In some embodiments, the present invention is directed to a method thatat least includes one or more of the following steps of: a) mechanicallypre-stretching an electro-active polymer film in a single or biaxialdirections to form a pre-stretched electro-active polymer film; b)attaching a first semi-stiff conductor to a first surface of theelectro-active polymer film and a second semi-stiff conductor to asecond surface, each semi-stiff conductor is configured to fix theelectro-active polymer film in a pre-stretched state; and c) coupling apair of mechanical connectors at each end of the active region.

In some embodiments, in order to maintain the electro-active polymerfilm in pre-stretch state on a single axis, a stretchable conductor isattached to the electro-active polymer (EAP) film which is, then,wrapped around a solid body. In some embodiments, the EAP actuator canbe covered on at least one side of the film by an isolating layer, whichis configured to resist the voltage that is applied on the EAP film. Insome embodiments, the isolating layer can prevent voltage breakthroughfrom the EAP actuator and the solid body.

In some embodiments, the required pre-stretch in a single axis of theEAP film can be determined by a visual indicator, e.g. a hills andvalley pattern with a solid strap or by pre-arranged guide lines or anyother kind of visual indicator. In some embodiments, afterpre-stretching the electro-active polymer film and attaching at leastone stretchable conductor, the film is attached to a solid mechanismthat fixes the film in a pre-stretch state in a single axis, whileallowing it to expand and be wrapped around a solid body on the otheraxis. In some embodiments, the solid mechanism can be parallel solidplastic straps attached to the electro active polymer film. In someembodiments, the plastic straps used to fix the pre-stretched film in asingle axis, can also be used to prevent the film from contracting inthe other axis, by attaching holders that keep the plastic straps at aminimal distance, while allowing them to expand. In some embodiments,the attachment of the solid mechanism can be made by gluing and/or anyother similarly method(s) of attachment.

In some embodiments, the attaching of a conductor is performed by atleast one methodology selected from the group consisting of printing,etching, brushing, water dispersion, gluing, and any combinationthereof. In some embodiments, the instant method further includes:folding the electro-active polymer X times, wherein X is between 2 and10,000. In some embodiments, the conductor is selected from the groupconsisting of a stretchable conductor, a rigid conductor in an expandingpattern, a printed conductor in an expanding pattern and any combinationthereof. In some embodiments, the printed conductor is made from atleast one of a conducting silver ink, a conducting carbon ink, and anycombination thereof. In some embodiments, the stretchable conductor ismade from networks of gold or carbon nano-particles embedded in elasticpolyurethane. In some embodiments, the stretchable conductor is madefrom carbon graphite powder with silicon oil, conducting silicon grease,Polyaniline (PAni) based solution, carbon black powder, conductingpolymer, conductive rubber and any combination thereof. In someembodiments, the expanding pattern is one of a zigzag pattern, andexpanding diamond pattern.

In some embodiments, the present invention is directed to an actuatorthat at least includes: a) at least one active region, having at leastone electro-active polymer layer; b) at least two conducting layersarranged on the surface of the electro-active polymer layer such thateach conducting layer is attached on each surface side of theelectro-active polymer layer in an expanding pattern afterpre-stretching of the electro-active polymer layer, thereby maintainingthe electro-active polymer layer in a pre-stretched state; and c) a pairof mechanical connectors at either end of the active region, wherein apositive connector is operably connected to one end of the at least oneactive region, and a negative connector is operably connected to theother end of the at least one active region.

In some embodiments, the actuator further includes at least one strainmeasuring mechanism for monitoring strain feedback for the at least oneactive region, whereby turning the actuator into a transducer, meaningthat mechanically stretching the actuator, creates an electric charge.In some embodiments, measuring the strain is based on measuring theelectric charge while stretching and contracting the actuator. In someembodiments, the actuator further includes at least one strain measuringmechanism for monitoring strain feedback for the at least one activeregion, whereby measuring the capacitance of the actuator can betranslated to measuring the actuator's strain. In some embodiments, theelectro-active polymer layer is mechanically pre-stretched during afabrication. In some embodiments, the expanding pattern is a zigzagpattern. In some embodiments, each conducting layer is a stretchableconductor. In some embodiments, a thickness of the electro-activepolymer layer is between 10 um-5 mm. In some embodiments, theelectro-active polymer is folded. In some embodiments, each conductinglayer is printed or etched to the electro-active polymer.

In some embodiments, the EAP actuator can be used for the constructionof an active compression bandage, including of: a bandage, which isplaced on a body part of an animal or a human being. For example, in thecase of human, the active compression bandage can be placed on, forexample, but not limited to, a leg, a calf, a foot, a hand or an arm.For example, the bandage is fixed on the body part, by using between 1to 20 elastic straps, which are wrapped around the body part, and areconnected to the bandage by Velcro, clip-on buttons, buttons, zipper,sewing or any other similar fixation method. In some embodiments, theelastic straps are stretched when wrapped around the body part. In someembodiments, the bandage and the elastic straps are threaded with EAPactuators. In some embodiments, by stretching the elastic straps, theEAP actuators are pre-stretched, and, then, are fixed in a pre-stretchstate.

In some embodiments, the bandage is connected to a control box, whichactivates and controls the EAP actuators activation. In someembodiments, the control box at least includes: a battery or aconnection to a power socket and an electrical circuit, which transformsthe battery or the connection to a power socket output voltage to therequired voltage for the EAP and activates and de-activates the EAPactuators, by applying voltage on each actuator, separately orsimultaneously, according to a pre-determined sequence. In someembodiments, the control box can also measure the expansion of the EAPactuator.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures constitute a part of this specification and includeillustrative embodiments of the present invention and illustrate variousobjects and features thereof. Further, the figures are not necessarilyto scale, some features may be exaggerated to show details of particularcomponents. In addition, any measurements, specifications and the likeshown in the figures are intended to be illustrative, and notrestrictive. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

FIG. 1 is a flow chart generally illustrating an exemplary procedure formaintaining an electro-active polymer in a pre-stretch state, accordingto some embodiments of the present invention.

FIG. 2 schematically illustrates an exemplary pre-stretchedelectro-active polymer, printed or etched with a conductor in a zigzagpattern, according to some embodiments of the present invention.

FIG. 3 schematically illustrates an exemplary electro-active polymer,printed or etched with a conductor in a zigzag pattern in an expandedstate, according to some embodiments of the present invention.

FIG. 4 schematically illustrates an example of an expanding pattern,according to some embodiments of the present invention.

FIGS. 5A and 5B are perspective views, showing an exemplaryelectro-active polymer actuator folded, according to some embodiments ofthe present invention.

FIGS. 6A and 6B schematically illustrate a top perspective view of anexemplary electro-active polymer transducer before and after applicationof a voltage in accordance with some embodiments of the presentinvention.

FIGS. 7A-7C are snapshots of an example of a stretching device intendedto biaxially or single axially pre-stretch an electro-active polymerfilm, in the fabrication process, according to some embodiments of thepresent invention.

FIG. 8 is a flow chart generally illustrating an exemplary procedure formaintaining an electro-active polymer in a pre-stretch state, accordingto some embodiments of the present invention.

FIGS. 9A-9C schematically illustrate a hills and valley pattern that canbe used as a visual indicator for wrapping the EAP film with the preciseamount of stretch, according to some embodiments of the presentinvention.

FIG. 10 is a snapshot that schematically illustrates an example of asolid mechanism for fixing the EAP film in a pre-stretch state in asingle axis, while allowing the film to expand in the other axis,according to some embodiments of the present invention.

FIGS. 11A-11C are snapshots that schematically illustrate examples of anexternal design of an active compression bandage for the leg, accordingto some embodiments of the present invention.

FIGS. 12A-12B are snapshots that schematically illustrate example(s) ofan internal mechanism that activates an active compression bandage forthe leg, built from EAP actuators, according to some embodiments of thepresent invention.

FIGS. 13A-13B are snapshots that schematically illustrate an example ofan addition to the solid mechanism for fixing the EAP film in apre-stretch state in a single axis, which prevents the film fromcontracting in the other axis, according to some embodiments of thepresent invention.

FIGS. 14A-14D are snapshots that schematically illustrate of an exampleof a stretching machine intended to biaxially or single axiallypre-stretch an electro-active polymer film, in the fabrication process,according to some embodiments of the present invention.

DETAILED DESCRIPTION

Reference will now be made to several embodiments of the presentinvention(s), examples of which are illustrated in the accompanyingfigures. Wherever practicable similar or like reference numbers may beused in the figures and may indicate similar or like functionality. Thefigures depict embodiments of the present invention for purposes ofillustration only. One skilled in the art will readily recognize fromthe following description that alternative embodiments of the structuresand methods illustrated herein may be employed without departing fromthe principles of the invention described herein. The terms, “forexample”, “e.g.”, “optionally”, as used herein, are intended to be usedto introduce non-limiting examples.

The phrases “in one embodiment” and “in some embodiments” as used hereindo not necessarily refer to the same embodiment(s), though it may.Furthermore, the phrases “in another embodiment” and “in some otherembodiments” as used herein do not necessarily refer to a differentembodiment, although it may. Thus, as described below, variousembodiments of the invention may be readily combined, without departingfrom the scope or spirit of the invention.

In addition, as used herein, the term “or” is an inclusive “or”operator, and is equivalent to the term “and/or,” unless the contextclearly dictates otherwise. The term “based on” is not exclusive andallows for being based on additional factors not described, unless thecontext clearly dictates otherwise. In addition, throughout thespecification, the meaning of “a,” “an,” and “the” include pluralreferences. The meaning of “in” includes “in” and “on.”

Throughout this description the term “Electro-Active Polymer,”“electro-active polymer” or “EAP” is used to indicate dielectricelastomer film(s) adapted to be stretched biaxially or in a single axis.The use of the term “EAP” is a general descriptive of a genus and shouldnot be limited to any particular shape, construction material and/orgeometry, and at least some embodiments of the present invention coverare directed to all suitable elastic materials, such as the 3M™ VHB™4910, 4905, 4955, 4959 or 9460 Tape, Dow Corning™ or Nusil™ siliconelastomer, Elastosil or Silpuran film by Wacker, or any other suitablesilicon or acrylic dielectric elastomer.

As used herein, a “conductor” refers to an object or type of materialthat allows the flow of electrical current in one or more directions.

In some embodiments, the present invention provides a method for keepingthe electro-active polymer film in a pre-stretched state/condition on asingle axis, by wrapping and fixing it around a solid body, e.g. a humanbody part.

In some embodiments, the instant method of the present invention atleast includes: a) mechanically pre-stretching an electro-active polymerfilm in a single or biaxial directions to form a pre-stretchedelectro-active polymer film; b) attaching a semi-stiff conductor to bothsurfaces of the electro-active polymer film, the semi-stiff conductor isconfigured to fix the electro-active polymer film in a pre-stretchedstate; and c) coupling a pair of mechanical connectors at each end ofthe active region.

In some embodiments, the attaching is performed by at least onemethodology selected from the group consisting of printing, etching,brushing, water dispersion, gluing, and any combination thereof. In someembodiments, the instant method further includes: folding theelectro-active polymer X times, wherein X is between 2 and 10,000. Insome embodiments, the conductor is selected from the group consisting ofa stretchable conductor, a rigid conductor in an expanding pattern, aprinted conductor in an expanding patter and any combination thereof.

In some embodiment, said conductor might be a stretchable conductor, forexample but not limited by, carbon or silver based conducting ink,Polyaniline (PAni) based solution, carbon based solution, carbon blackpowder, conducting polymer, conductive rubber, conductive silver orcarbon paste, conductive epoxy, conducting grease, laser cut or moldedrigid conducting sheet in an expanding pattern, graphite powder basedsolution, stretchable conducting sheet made by networks of gold and/orcarbon nano-particles embedded in elastic polyurethane or anycombination thereof. In some embodiment, said conductor might beattached to the EAP film by, for example but not limited to, printing,etching, brushing, water dispersion, gluing and/or any other similarlysuitable method(s) of attachment or any combination thereof.

In some embodiment, the inventive EAP film of the present invention canbe used as a compression device or force feedback device.

In some embodiments, the stretchable conductor is made from carbon blackpowder. In some embodiments, the stretchable conductor is made from aconductive polymer. In some embodiments, the stretchable conductor ismade from conductive rubber. In some embodiments, the expanding patternis one of a zigzag pattern, and expanding diamond pattern.

In some embodiments, the instant actuator of the present invention atleast includes: a) at least one active region, having at least oneelectro-active polymer layer; b) at least two conducting layers arrangedon the surface of the electro-active polymer layer such that eachconducting layer is attached on each surface side of the electro-activepolymer layer in an expanding pattern after pre-stretching of theelectro-active polymer layer, thereby maintaining the electro-activepolymer layer in a pre-stretched state; and c) a pair of mechanicalconnectors at either end of the active region, wherein a positiveconnector is operably connected to one end of the at least one activeregion, and a negative connector is operably connected to the other endof the at least one active region.

In some embodiments, the actuator further includes at least one strainmeasuring mechanism for monitoring strain feedback for the at least oneactive region, whereby turning the actuator into a transducer, meaningthat mechanically stretching the actuator, creates an electric charge.In some embodiments, measuring the strain is based on measuring theelectric charge while stretching and contracting the actuator. In someembodiments, the exemplary actuator further includes at least one strainmeasuring mechanism for monitoring strain feedback for the at least oneactive region, whereby measuring the capacitance of the actuator can betranslated to measuring the actuator's strain. In some embodiments, theelectro-active polymer layer is mechanically pre-stretched during afabrication. In some embodiments, the expanding pattern is a zigzagpattern. In some embodiments, each conducting layer is a stretchableconductor. In some embodiments, a thickness of the electro-activepolymer layer is between 10 um-5 mm. In some embodiments, theelectro-active polymer is folded. In some embodiments, each conductinglayer is printed or etched to the electro-active polymer.

In some embodiments, the present invention provides a method for keepingthe electro-active polymer in a pre-stretched state/condition by coatingthe electro-active polymer with a stiffened material such as, but notlimited to, a semi-stiff or stretchable conductor layer on both sides,and utilizing the semi-stiff conductor in a zigzag pattern or any othersuitable expanding method, such as, but not limited to, the networks ofgold or carbon nano-particles embedded in elastic polyurethane on thesurface of the electro-active polymer.

In some embodiments, the present invention provides electro-activepolymers, transducers and/or devices that maintain pre-stretch conditionin one or more portions of an electro-active polymer. In someembodiments, electro-active polymers described herein includes apre-stretched portion and at least one conductor configured to maintainthe pre-stretch condition in the pre-stretched portion. In someembodiments, an exemplary conductor is in a form of a semi-stiffconductor made, for example but not limited to, by a conducting ink(e.g., silver and/or carbon based conductive ink, for example CreativeMaterials, Inc. 125-10 silver based electrically conductive ink(http://www.creativematerials.com/data-sheets/page-4/) or CreativeMaterials, Inc. 112-48 carbon based conductive ink)(http://www.creativematerials.com/data-sheets/). In some embodiments,the exemplary conductor is in a form of a stretchable conductor, suchas, for example, a stretchable electrical conductor that is created outof networks of gold and/or carbon nano-particles embedded in elasticpolyurethane. In some embodiments, the exemplary conductor is made froma carbon black powder layer attached to the electro-active polymer, forexample but not limited to, Ketjenblack EC-600JD powder by Akzo Nobel,Super C 65 by C-Nergy or 250P by Enscao. In some embodiments, theexemplary conductor is made from carbon or silver paste, for example butnot limited to WIK20489-56A by Henkel. In some embodiments, theexemplary conductor is made from carbon or silver conductive epoxy, forexample but not limited to H20E by Epo-Teck. In some embodiments, theexemplary conductor is made by Polyaniline (PAni) based solution, carbonbased solution, a laser cut or molded rigid conducting sheet, or anycombination thereof.

The term “pre-stretch,” and its variants are being used herein todescribe mechanically stretching of an electro-active polymer film in asingle axis or biaxial planar direction prior to activation. In someembodiments, by maintaining the EAP in the pre-stretch state/condition,the instant invention allows to at least:

i) enhance the electrical breakdown strength,

ii) minimize or eliminate pull-in instability; and/or

iii) decrease the EAP film's thickness, thus requiring a lower voltageto obtain the same electrostatic pressure.

In some embodiments, the term “pre-stretch” is referred to anymechanical stretch from 10%-5000% of the electro-active polymer filmoriginal size. In some embodiments, the “pre-stretch” is referred to anymechanical stretch from 10%-100% of the electro-active polymer filmoriginal size. In some embodiments, the term “pre-stretch” is referredto any mechanical stretch from 50%-100% of the electro-active polymerfilm original size. In some embodiments, the term “pre-stretch” isreferred to any mechanical stretch from 50%-1000% of the electro-activepolymer film original size. In some embodiments, the term “pre-stretch”is referred to any mechanical stretch from 100%-5000% of theelectro-active polymer film original size. In some embodiments, the term“pre-stretch” is referred to any mechanical stretch from 1000%-5000% ofthe electro-active polymer film original size. In some embodiments, theterm “pre-stretch” is referred to any mechanical stretch from2500%-5000% of the electro-active polymer film original size.

In some embodiments, the exemplary conductor fixes the pre-stretchportion in the pre-stretch condition, while allowing the electro-activepolymer to change size in a specific direction or directions. In someembodiments, the exemplary conductor, discussed herein, is a conductorthat is sufficiently stiff to fix the EAP in a pre-stretch state, whileallowing the EAP to expand. In some embodiments, the change in size ofthe EAP is due to an exemplary method of attaching the exemplaryconductor on the EAP in accordance with some embodiments of the presentinvention and not due to a characteristic of the exemplary conductoritself.

In some embodiments, the present invention provides electro-activepolymers, transducers and/or devices that maintain a pre-stretchstate/condition in one or more portions of an electro-active polymer. Insome embodiments, electro-active polymers described herein include atleast one pre-stretched portion attached to at least one conductor whichis configured to maintain the electro-active polymer film in the leastone pre-stretched portion in the pre-stretch state/condition.

In some embodiments, an exemplary conductor utilized by the presentinvention can be a semi-stiff conductor or a stretchable conductor. Insome embodiments, the exemplary conductor utilized by the presentinvention can fix the electro-active polymer film in the pre-stretchstate/condition, while allowing the electro-active polymer to changesize in a specific direction or directions.

In some embodiments, the present invention is directed to a method formaintain an electro-active polymer film in a pre-stretched state, wherethe method at least includes the steps of:

i) pre-stretching the electro-active polymer film, by mechanicallystretching the film in a single or biaxial directions;

ii) attaching at least one conductor to at least one surface of theelectro-active polymer film, by, for example but not limited to,printing, etching, brushing, water dispersion, gluing and/or any othersimilarly suitable method(s) of attachment;

iii) where the at least one conductor has semi-stiff properties (e.g.,the conductor enables the electro-active polymer to expand);

iv) maintaining conductivity of at least one conductor at a level of atleast 0.1% of its original conductivity, while the at least oneconductor being stretched for more than 5%; and

v) mechanically fixing the electro-active polymer film being in apre-stretched state.

In some embodiments, the exemplary method of the present inventionfurther includes using more than one layer and up to 10,000 layers ofelectro-active polymer films in order to improve, for example, strength(e.g., allowing the activation based on application of sufficientlystrong forces) and/or durability (e.g., minimizing physical damage(e.g., tear).

In some embodiments, the exemplary method of the present inventionfurther includes using more than one layer and up to 1,000 layers ofelectro-active polymer films in order to improve strength and/ordurability of the actuator. In some embodiments, the exemplary method ofthe present invention further includes using more than one layer and upto 100 layers of electro-active polymer films in order to improvestrength and/or durability of the actuator.

In some embodiments, multi-layered structure(s) of electro-activepolymer films of the present invention is/are made by, for example butnot limited to, folding a single film, attaching multiple films to eachother, and/or any combination thereof.

In some embodiments, the exemplary semi-stiff conductor utilized inaccordance with the present invention is selected from the groupconsisting of a stretchable conductor, a rigid conductor in an expandingpattern, a printed conductor in an expanding pattern, and anycombination thereof.

In some embodiments, the exemplary stretchable conductor utilized inaccordance with the present invention can be created out of networks ofgold and/or carbon nano-particles embedded in elastic polyurethane, orany other suitable stretchable conductor.

In some embodiments, the exemplary stretchable conductor utilized inaccordance with the present invention can be created by a layer ofcarbon black powder glued to the electro-active polymer or any othersuitable stretchable conductor.

In some embodiments, the exemplary stretchable conductor utilized inaccordance with the present invention can be created by a conductingpolymer or any other suitable stretchable conductor.

In some embodiments, the exemplary stretchable conductor utilized inaccordance with the present invention can be created by a conductingrubber or any other suitable stretchable conductor.

In some embodiments, the exemplary stretchable conductor utilized inaccordance with the present invention can be created by applying acarbon or silver paste or any other suitable stretchable conductor.

In some embodiments, the exemplary stretchable conductor utilized inaccordance with the present invention can be created by applying acarbon or silver epoxy or any other suitable stretchable conductor.

In some embodiments, the exemplary rigid conductor utilized inaccordance with the present invention can be created by laser cutting,molding and/or etching a solid conductor. In some embodiments, theexemplary printed conductor utilized in accordance with the present canbe a made utilizing a conducting ink based on silver and/or carbon.

In some embodiments, an exemplary expanding pattern utilized inaccordance with the present invention refers to one of a zigzag pattern,an expanding diamond pattern or any other suitable expanding pattern.

In some embodiments, the attachment of an exemplary conductor to anelectro-active polymer is done by printing, etching, brushing, waterdispersion, gluing, ion-attachment and/or any other suitable method ofthe attachment.

In some embodiments, an exemplary actuator can be activated by applyingan electric charge on the conducting layers attached to theelectro-active polymer film, thus creating an electric field whichexpands the electro-active polymer film in a single axis or biaxialdirection. In some embodiments, the activation creates an expansion ofthe exemplary actuator by 3%-100% in a single axis or biaxial directionsfrom its original size. In some embodiments, the activation creates anexpansion of the exemplary actuator by 3%-500% in a single axis orbiaxial directions from its original size. In some embodiments, theactivation creates an expansion of the exemplary actuator by 3%-1000% ina single axis or biaxial directions from its original size. In someembodiments, the activation creates an expansion of the exemplaryactuator by 50%-1000% in a single axis or biaxial directions from itsoriginal size. In some embodiments, the activation creates an expansionof the exemplary actuator by 100%-1000% in a single axis or biaxialdirections from its original size. In some embodiments, the activationcreates an expansion of the exemplary actuator by 500%-1000% in a singleaxis or biaxial directions from its original size.

In some embodiments, variables that affect the expansion and thedirection of the expansion include, but are not limited to:

i) an amount and/or a direction of the pre-stretch;

ii) an electrical charge being applied (e.g., between 10V-20,000V,between 100V-20,000V, between 1000V-20,000V, between 10V-1,000V, between10V-10,000V, between 10,000V-20,000V);

iii) a method and/or a type of fixation/attachment; and

iv) any combination thereof.

In some embodiments, the methods of the present invention utilize atleast one actuator that includes at least the following components:

A. at least one active region, having at least one electro-activepolymer layer;

B. at least two conducting layers arranged on the surface of the atleast one electro-active polymer layer such that each conducting layeris attached on each surface side of the at least one electro-activepolymer layer in an expanding pattern after pre-stretching of the atleast one electro-active polymer layer, thereby maintaining the at leastone electro-active polymer layer in a pre-stretched state; and

C. a pair of mechanical connectors at either end of the at least oneactive region, wherein a positive connector is operably connected to oneend of the at least one active region, and a negative connector isoperably connected to the other end of the at least one active region.

In some embodiments, the exemplary actuator in accordance with thepresent invention further includes at least one component configured formonitoring strain, whereby the exemplary actuator acts as a transducer,i.e., the mechanically stretching of the actuator results in generatingan electric charge. In some embodiments, amount of the electrical chargebeing generated depends on at least the following, but not limited to,amount of stress being applied on the actuator and thus can be used as astretch, force and/or bend sensor.

In some embodiments, the exemplary actuator in accordance with thepresent invention further includes at least one component configured formonitoring strain, whereby measuring the capacitance of the actuator canbe translated to measuring the actuator's strain. In some embodiments,amount of the change in the capacitance of the actuator depends on atleast the following, but not limited to, amount of stress being appliedon the actuator and thus can be used as a stretch, force and/or bendsensor.

In some embodiments, the exemplary actuator includes at least one strainmeasuring mechanism for monitoring strain feedback for the at least oneactive region whereby acting as a transducer. In some embodiments, thestrain measuring mechanism can be based on calculations described in Li,et al., “Effect of mechanical pre-stretch on the stabilization ofdielectric elastomer actuation,” J. Phys. D: Appl. Phys. 44 (2011)155301, whose this specific disclosure is hereby incorporated herein byreference.

In some embodiments, the electro-active polymer film can bepre-stretched:

1) during fabrication, and/or

2) prior or after to the attachment of the semi-stiff conductor.

In some embodiments, the pre-stretch condition is reached by utilizingany suitable physical mechanisms that stretch the electro-active polymerfilm in a single axis or biaxial directions.

In some embodiments, the exemplary expanding pattern, but not limitedto, is a zigzag pattern (see FIGS. 2 and 3) that is utilized to attacheach conducting layer to the surface of the corresponding electro-activepolymer layer. In some embodiments, the exemplary expanding pattern, butnot limited to, is any other expanding pattern (e.g., an expandingdiamond pattern shown in FIG. 4). In some embodiments, the expandingmechanism that each conducting layer is attached to the surface of theelectro-active polymer layer is applied by a stretchable conductor(e.g., the stretchable conductor created out of networks of gold and/orcarbon nano-particles embedded in elastic polyurethane; any othersuitable stretchable conductor).

In some embodiments, the electro-active polymer film layer has thicknessbetween 10 um-5 mm. In some embodiments, the electro-active polymer filmlayer has thickness between 100 um-5 mm. In some embodiments, theelectro-active polymer film layer has thickness between 1000 um-5 mm. Insome embodiments, the electro-active polymer film layer has thicknessbetween 10 um-1 mm. In some embodiments, the electro-active polymer filmlayer has thickness between 100 um-1 mm. In some embodiments, theelectro-active polymer film layer has thickness between 500 um-1 mm.

In some embodiments, each conducting layer is attached to theelectro-active polymer layer by, for example but not limited to, atleast one of printing (e.g., utilizing conductive ink), etching (e.g.,using a solution of electrolyte), brushing (e.g., using carbon graphitepowder with silicon oil), water dispersion (e.g., using PAni basedsolution), gluing (e.g., gluing a laser cut or molded into an expandingpattern such as zigzag, rigid conducting sheet), and any other suitableapplicable method(s).

In some embodiments, electro-active polymers that are pre-stretchedimprove conversion between electrical and mechanical energy. In someembodiments, the pre-stretch state/condition stabilizes the actuation ofthe electro-active polymer due to at least one of:

i) minimizing or eliminating the pull-in instability by generatingelectrostriction (the pull-in instability identifies a state, whenvoltage is applied on an electro-active polymer film, causing the filmto thin down—e.g., voltage produces a higher electric field, whichsqueezes the electro-active polymer film as a positive feedback until anelectrical breakdown, based on calculations described in “Pull-in andwrinkling instabilities of electroactive dielectric actuators,” J. Phys.D: Appl. Phys. 43 (2010) 325501, whose this specific disclosure ishereby incorporated herein by reference;

ii) improving the breakdown strength, and

iii) reducing the films thickness, which consequently lowers thevoltages required for activation. (for example, the voltage required toactivated 3M VHB 4910 film, is 50 KV per 1 mm. pre-stretching the filmbiaxially by 10, reduces the film thickness to 0.1 mm and the activationvoltage to 5 KV). For example, in some embodiments, when pre-stretched,acrylic copolymer elastomers (e.g., 3M VHB 4910 or VHB 4905 by 3MCorporation) produce a stable comparatively high and reversibleelectromechanical stretch of 3% to 1000% in area of the linear stretch.

In the drawings:

FIG. 1 is a flow chart generally illustrating an exemplary procedure formaintaining an electro-active polymer in the pre-stretchstate/condition, according to some embodiments of the present invention.In some embodiments, this procedure can include at least the steps of:

i) mechanically and biaxially pre-stretching an electro-active polymerfilm (step 1);

ii) attaching the electro-active polymer with semi-stiff conductor byone of the following ways, but not limited to: printing (e.g.,conducting ink), etching (e.g. by using a solution of electrolyte),brushing (e.g. using carbon graphite powder with silicon oil), waterdispersion (e.g. using PAni based solution), gluing (e.g. gluing a lasercut or molded into an expanding pattern such as zigzag or expandingdiamond pattern, rigid conducting sheet), or any other suitableattachment method(s) (step 2);

iii) coupling a pair of mechanical connectors at either end of theactive region of the electro-active polymer (step 3); and

iv) optionally, folding the electro-active polymer in order to improvecapabilities of an actuator (i.e., the electro-active polymer with theattached conductor) (step 4).

In some embodiments, by coating the electro-active polymer with asemi-stiff conductor layer from both sides and arranging the conductorin a zigzag pattern (or any other suitable expanding pattern), themethod(s) of the present invention allows the electro-active polymer toexpand linearly while keeping the pre-stretch state.

FIG. 2 shows an exemplary electro-active polymer that can be used inaccordance with some embodiments of the present invention. As FIG. 2shows, the electro-active polymer can be used as a linear actuator. Theelectro-active polymer, generally indicated by numeral 10 in the FIG. 2,includes at least: a layer of semi-stiff conductor 11 printed on bothsides of its surfaces. In some embodiments, the semi-stiff conductorlayer 11 is printed or etched in a zigzag form, such that the deploymentform of the semi-stiff conductor 11 keeps the electro-active polymer ina pre-stretched state while allowing it to expand in a linear direction.FIG. 3 schematically illustrates the exemplary electro-active polymer 10in an expanded state.

Although the maintaining/strengthening/expanding pattern of thesemi-stiff conductor 11 is shown with respect to the zigzag form, otherforms of maintaining patterns can also be used, such as a expandingdiamond pattern. FIG. 4 schematically illustrates an example of alattice work form, according to some embodiments of the presentinvention.

In some embodiments, as illustrated in at least some figures, thearrangement of the exemplary electro-active polymer with the exemplaryconductor results in a flat and flexible linear actuator which can fold.

FIG. 5A is a perspective view, showing an exemplary pre-stretchedelectro-active polymer 10 folded in order to improve capabilities of theactuator, according to some embodiments of the invention. FIG. 5A showsthe exemplary electro-active polymer 10 to be folded in an alternatingfolding pattern. FIG. 5B is a perspective view, showing the linearexpansion of the exemplary folded electro-active polymer 10, having apair of mechanical connectors (12 and 13) at each end of an activeregion of the electro-active polymer 10.

FIGS. 6A and 6B schematically illustrate a top perspective view of anexemplary electro-active polymer transducer 60 before (FIG. 6A) andafter (FIG. 6B) application of a voltage, in accordance with someembodiments of the present invention. In some embodiments, thetransducer (60) includes an exemplary EAP (61) with a conductive coatingthat is activated by electrostatic forces between two compliantelectrodes (62), which are fundamentally capacitors that change theircapacitance when a voltage is applied by allowing the polymer tocompress in thickness and expand in area due to the electric field (theexpansion is indicated by the black arrows in FIG. 6B).

FIGS. 7A-7C shows an example of a stretching device intended tobiaxially or single axially pre-stretch a transparent electro-activepolymer film. The EAP film is fixed by 8 connectors to the stretchingdevice, which expands the film in the desired directions (e.g.,biaxial). The stretching device can be used in step 1 of FIG. 1 formechanically biaxially pre-stretching an electro-active polymer film inthe exemplary procedure for maintaining an electro-active polymer in thepre-stretch state/condition. FIG. 7A shows a biaxially stretched EAPfilm, which is further stretched in FIGS. 7B and 7C, until the filmreaches its desired pre-stretched state of 500% of its original size onFIG. 7C.

The term semi-stiff conductor is being used to describe a stretchableconductor or a rigid conductor in an expanding pattern that onceattached to the EAP is rigid enough to hold the EAP in a pre-stretchedstate, while allowing the EAP to expand. For example, on a 1×1 cm2 3M4905 VHB tape, equally biaxially pre-stretched √{square root over (5)}times of the film's original size, meaning that the 1×1 cm2 film wasstretched by times of the film's original size in length (X axis) and inwidth (Y axis). The conductor won't compress by more than 10%, due to amechanical compression force of at least 500N on the X axis and on the Yaxis, on a 1×1 cm2 surface. Meanwhile, the conductor allows the EAP filmto mechanically expand by at least 7% on a single or both axis, whilemaintaining at least 5% of its conductivity for every 7% of expansion.

The precise compression force the conductor will be able to resist, andthe expansion the conductor can perform while maintaining conductivity,is determined by the material the conductor is made of, the shape, sizeand pattern of the conductor and the method of attaching the conductorto the EAP.

Exemplary Methods and Mechanisms for Maintaining an Electro-ActivePolymer Film in a Pre-Stretch State by Wrapping it Around a Solid Body

FIG. 8 is a flow chart generally illustrating an exemplary procedure formaintaining an electro-active polymer in the pre-stretchstate/condition, according to some embodiments of the present invention.In some embodiments, this procedure can include at least the steps of:

mechanically biaxially pre-stretching an electro-active polymer film(step 71);

attaching at least one semi-stiff or stretchable conductor to thepre-stretched electro-active polymer with one of the following ways, butnot limited to: printing (e.g., conducting ink), etching (e.g. by usinga solution of electrolyte), brushing (e.g. using carbon graphite powderwith silicon oil), water dispersion (e.g. using PAni based solution),gluing (e.g. gluing a laser cut or molded into an expanding pattern suchas zigzag or expanding diamond pattern, rigid conducting sheet), or anyother suitable attachment method(s) (step 72);

coupling a pair of mechanical connectors at either end of the activeregion of the electro-active polymer (step 73);

folding the electro-active polymer film in order to improve capabilitiesof an actuator (i.e., the electro-active polymer with the attachedconductor) (step 74); and

wrapping the electro-active polymer film around a solid body andfixing/maintaining (e.g., securing, attaching) it in that state, to keepthe film in a pre-stretched state (step 75).

FIG. 10 schematically illustrates an example of a solid mechanism forfixing the EAP film in a pre-stretch state in a single axis, whileallowing the film to expand in the other axis.

In some embodiments, the electro-active polymer film might be fixed in apre-stretched state on a single axis, by a solid mechanism, for examplebut not limited to, parallel solid plastic straps attached to the EAPfilm (such as in FIG. 10), allowing the EAP film to expand and bewrapped around a solid body on the other axis. In some embodiments, theattachment of the solid mechanism can be made, for example but notlimited to, gluing and/or any other similarly method(s) of attachment.FIG. 10 shows an example in which parallel solid plastic straps (90) areattached to an EAP film (91) thus maintaining the film pre-stretch on asingle axis (in the direction of the plastic straps), but also allowingthe EAP film to expand in the other axis. In some embodiment, the solidplastic straps might be 1 mm-80 cm wide. In some embodiment, the solidplastic straps might be 1 mm-20 cm wide. In some embodiment, the solidplastic straps might be 1 cm-80 cm wide. In some embodiment, the solidplastic straps might be 1 cm-20 cm wide. In some embodiment, the solidplastic straps might be 1 cm-60 cm wide. In some embodiment, the solidplastic straps might be placed in distance of 1 mm-50 cm apart. In someembodiment, the solid plastic straps might be placed in distance of 1cm-50 cm apart. In some embodiment, the solid plastic straps might beplaced in distance of 1 cm-30 cm apart. In some embodiment, the solidplastic straps might be placed in distance of 1 cm-20 cm apart. In someembodiment, the solid plastic strap might be placed in parallel or anyangle between 180° to 90° from each other. In some embodiment, theplastic straps can be made from polypropylene, polystyrene, polyethyleneor any other similar type plastic.

In some embodiments, the plastic straps used to fix the pre-stretchedfilm is a single axis, can also be used to prevent the film fromcontracting in the other axis, by attaching holders that keep theplastic straps at a minimal distance, while allowing them to expand. Insome embodiments, the holder can be made by using an elastic wire, witha rigid cover, in the space between the plastic straps (such as in FIGS.13A-13B)

In some embodiments, the precise pre-stretch of the electro-activepolymer film, can be determined by visual indicator, e.g. a hills andvalleys pattern with a solid strap (such as in FIG. 9A-9C) or bypre-arranged guide lines or any other kind of visual indicator.

FIGS. 9A-9C schematically illustrate a hills and valley pattern that canbe used as a visual indicator for wrapping the EAP film with the preciseamount of stretch. FIG. 9A shows an EAP film (81) attached to a strap(80) (for example polypropylene, flat nylon, polyester, seatbelt strapor any other strap), on multiple joints, when the strap's length islonger than the EAP film's length, causing a hills and valleys patternon the strap. FIG. 9B shows that the EAP film (81), can be linearlystretched while the strap (80) remains loose. FIG. 9C shows that thestrap limits the linear stretch of the EAP film, due to the strapfirmness, thus preventing tear in the EAP film, and giving a visualindicator for when the EAP film is precisely pre-stretched, whichhappens when the strap and the EAP film are in the same length.

In some embodiments, the present invention is directed to a method formaintain an electro-active polymer film in a pre-stretched state, wherethe method at least includes the steps of:

pre-stretching the electro-active polymer film, by mechanicallystretching the film in a single or biaxial directions;

fixing the EAP film in a pre-stretch state on a single axis, byattaching straps that allow the EAP film to expand in the other axis,by, for example but not limited to, gluing and/or any other similarlymethod(s) of attachment;

attaching at least one conductor to at least one surface of theelectro-active polymer film, by, for example but not limited to,printing, etching, brushing, water dispersion, gluing and/or any othersimilarly suitable method(s) of attachment;

at least one of said conductor, features the capability of maintainingconductivity at a level of at least 5% while being stretched for morethan 5%;

wrapping and fixing the electro active polymer film around solid body,for example but not limited to a human body part; and

fixation can be made by Velcro, clip-on button, buttons, zipper or anyother similar fixation method.

Exemplary Embodiments of Electro-Active Polymer Based CompressionBandage Made in Accordance with the Present Invention.

In some embodiments, the EAP actuator can be used for the constructionof an active compression bandage, including of: a bandage, which isplaced on a body part, for example, but not limited to, a leg, a calf, afoot, a hand or an arm; for example, the bandage is fixed on the bodypart, by using, for example, between 1 to 20 elastic straps (can be inanother similarly suitable attaching mechanism), which are, for example,wrapped around the body part, and are connected to the bandage byVelcro, clip-on buttons, buttons, zipper, sewing or any other similarfixation device and method. In some embodiments, the elastic straps arestretched when wrapped around the body part. In some embodiments, thebandage and the elastic straps are threaded with EAP actuators. In someembodiments, by stretching the elastic straps, the EAP actuators arepre-stretched, and, then, are fixed in a pre-stretch state.

In some embodiments, the bandage is connected to a control box, whichactivates and controls the EAP actuators activation. In someembodiments, the control box at least includes: a battery and anelectrical circuit, which transforms the battery output voltage to therequired voltage for the EAP and activates and de-activates the EAPactuators, by applying voltage on each actuator, separately orsimultaneously, according to a pre-determined sequence.

In some embodiments, the control box can include a feedback mechanismconfigured to measure the pressure applied by the EAP actuator, and/orconfigured to adjust the voltage applied on the EAP actuator so as toresult in achieving the required pressure.

In some embodiments, the control box can include a feedback mechanismconfigured to monitor heart rate and/or a blood flow, so as tosynchronize the EAP actuators activation timing accordingly.

In some embodiments, the electrical charge being applied on the EAP isbetween 10-20,000 volts. In some embodiments, the electrical chargebeing applied on the EAP is between 100-20,000 volts. In someembodiments, the electrical charge being applied on the EAP is between1,000-20,000 volts. In some embodiments, the electrical charge beingapplied on the EAP is between 10-1,000 volts. In some embodiments, theelectrical charge being applied on the EAP is between 10-10,000 volts.In some embodiments, the electrical charge being applied on the EAP isbetween 10,000-20,000 volts.

In some embodiments, the bandage is fixed on the body part by usingbetween 1-15 straps. In some embodiments, the bandage is fixed on thebody part by using between 1-10 straps. In some embodiments, the bandageis fixed on the body part by using between 1-5 straps. In someembodiments, the bandage is fixed on the body part by using between 5-20straps. In some embodiments, the bandage is fixed on the body part byusing between 10-20 straps. In some embodiments, the bandage is fixed onthe body part by using between 15-20 straps.

In some embodiments, the required stretch of the strap can be determinedby a visual indicator, e.g. a hills and valley pattern with a solidstrap or by pre-arranged guide lines or any other kind of visualindicator.

In some embodiments, activating the EAP actuator provides pressure ofbetween 10 mmHg and 200 mmHg on the body part.

In some embodiments, the activation of the EAP actuators can be made toapply static compression, sequential compression, segmental compression,intermittent compression, or any other type of compression. In someembodiments, the active compression bandage can be used for theprevention and\or treatment for various vascular or lymphatic diseases,for example, but not limited to, DVT (Deep Vein Thrombosis), lymphedema,varicose veins, spider veins, CVI (Chronic Venous Insufficiency),ulcers, superficial venous thrombosis or phlebitis and diabetic wounds.In some embodiments, the active compression bandage can be used for theprevention and\or treatment and\or reduction of, for example, but notlimited to, scar tissue, swelling, sore muscles, burn wounds,cellulitis, chronic edema, eczema, infected wounds and epidermolysisbullosa. In some embodiments, the active compression bandage can be usedto reduce the recovery time of orthopedic surgeries, swelling,infections and sport injuries.

In some embodiments, the active compression bandage might includefeedback mechanism, which measures the pressure applied by the EAPactuator. In some embodiments, the feedback mechanism can be made by apressure sensor. In some embodiments, the active compression bandagemight include a heart rate monitor or a blood flow monitor. In someembodiments, said monitor is used to synchronize the timing of theactivation of the EAP actuators.

In some embodiments, the active compression bandage is controlled by acontrol unit. In some embodiments, the control unit might be batteryoperated. In some embodiments, the control signal from said control unitis a voltage. In some embodiments, the control unit controls the appliedpressure and the timing of the EAP actuators.

In some embodiments, the active compression bandage can be formed as astocking or legging to be put on the leg.

In some embodiments, wrapping the elastic strap will stretch the EAPstrap by between 20% and 1000%. In some embodiments, wrapping theelastic strap will stretch the EAP strap by between 20% and 500%. Insome embodiments, wrapping the elastic strap will stretch the EAP strapby between 50% and 1000%. In some embodiments, wrapping the elasticstrap will stretch the EAP strap by between 100% and 1000%. In someembodiments, wrapping the elastic strap will stretch the EAP strap bybetween 100% and 500%. In some embodiments, wrapping the elastic strapwill stretch the EAP strap by between 50% and 800%.

In some embodiments, the active compression bandage can be formed as astocking to be put on the leg. In some embodiments, the activecompression bandage can be formed to use on various body parts, forexample, the leg, the calf, the hip, the hand, the arm, the shoulder,the foot or any other body part.

The term “activating the EAP actuator” is used to describe a process ofdischarging the electric charge from the EAP actuator by at least 8%,causing the EAP actuator to contract by at least 5%. The exact amount ofcontraction, will be determined by the amount of pre-stretch, the typeof conductor used, the method of attachment for said conductor, thenumber of layers of EAP film the EAP actuator is comprised from and theamount of the electric charge being released.

The term “active compression bandage” refers to a device, which appliesdifferent compression on a body part. The pressure is higher when thebandage's actuator is activated (e.g., but not limited to, between 10mmHg and 200 mmHG), and lower when the bandage's actuator isde-activated/not active (e.g., but not limited to, between 0 mmHg and 80mmHg).

In some embodiments, while the EAP actuator is not active, the activecompression bandage applies pressure of between 0 mmHg and 80 mmHg. Insome embodiments, while the EAP actuator is not active, the activecompression bandage applies pressure of between 5 mmHg and 80 mmHg. Insome embodiments, while the EAP actuator is not active, the activecompression bandage applies pressure of between 0 mmHg and 30 mmHg. Insome embodiments, while the EAP actuator is not active, the activecompression bandage applies pressure of between 5 mmHg and 40 mmHg.

In some embodiments, activating the EAP actuator provides pressure ofbetween 10 mmHg and 200 mmHg on the body part. In some embodiments,activating the EAP actuator provides pressure of between 10 mmHg and 100mmHg on the body part. In some embodiments, activating the EAP actuatorprovides pressure of between 20 mmHg and 200 mmHg on the body part. Insome embodiments, activating the EAP actuator provides pressure ofbetween 20 mmHg and 100 mmHg on the body part. In some embodiments,activating EAP actuator provides pressure of between 30 mmHg and 130mmHg on the body part.

FIGS. 11A-11C schematically illustrate an example for an external designof an active compression bandage for the leg. FIG. 11A show a front viewof the active compression bandage on a leg. Three elastic straps (101)are wrapped and stretched around the leg, and are fixed to the bandage(103) by Velcro. The active compression bandage is controlled by acontrol box (102). An additional strap (104) is used to indicate thecorrect location for the placement of the active compression bandage onthe leg. FIG. 11B show a rear view of the active compression bandage ona leg. FIG. 11C shows a side view of the active compression bandage,unworn, showing the Velcro connectors (105).

FIGS. 12A-12B schematically illustrate an example for an internalmechanism that activates a compression bandage for the leg, built fromEAP actuators. FIG. 12A shows a front view of the internal constructionof the active compression bandage on a leg. Three elastic straps (101)are wrapped and stretched around the leg, pre-stretching the EAPactuator (116) and fixing it around the leg. The active compressionbandage is controlled by a control box (112). An additional strap (114)is used to indicate the correct location for the placement of the activecompression bandage on the leg. FIG. 12C shows a side view of theinternal construction of the active compression bandage, worn butwithout the leg, showing that the EAP actuator (116) is fully wrappedaround the leg, giving a full peripheral compression when activated.

FIGS. 13A-13B schematically illustrate an example of an addition to thesolid mechanism for fixing the EAP film in a pre-stretch state in asingle axis, by using an elastic wire (101) which is threaded throughholes in the plastic holders (100 & 110). The wire has a rigid cover(111) in space between the holders, which prevents the film fromcontracting in the other axis, while allowing it to expand.

FIGS. 14A-14D show an example of a stretching machine intended tobiaxially or single axially pre-stretch an electro-active polymer film.A roll of EAP film tape is held on a bar (151). Two rolling bars (152)pull the EAP film from the roll, and separate it from its protectingliner. The film is later attached to a moving rail (153). The speeddifference between the two rolling bars (152) and the moving rail (153),stretches the EAP film in the axis of the moving rail. The moving raillater expands (154) until it gets to its final width (155). The railsexpansion, stretches the EAP film perpendicularly to the axis of themoving rail.

All the above description and examples have been given for the purposeof illustration and are not intended to limiting in any way. Manydifferent mechanism(s) and modification(s) may become apparent to thoseof ordinary skill in the art.

What is claimed is:
 1. A method, comprising: fixing an electro-activepolymer film in a pre-stretched state, wherein the electro-activepolymer film has been pre-stretched in at least one planar stretchdirection; wherein the fixing is at least one of: i) attaching: 1) atleast one first semi-stiff conductor to a first surface of thepre-stretched electro-active polymer film, and 2) at least one secondsemi-stiff conductor to a second surface of the pre-stretchedelectro-active polymer film, wherein the second surface is opposite tothe first surface; wherein the at least one first and the at least onesecond semi-stiff conductors are configured to: a) fix the pre-stretchedelectro-active polymer film in a pre-stretched state to form a fixedpre-stretched electro-active polymer film and b) allow the fixedpre-stretched electro-active polymer film to expand; or ii) attaching 1)at least one stretchable conductor to at least one surface of thepre-stretched electro-active polymer film, and 2) wrapping thepre-stretched electro-active polymer film to a solid body to form thefixed pre-stretched electro-active polymer film; wherein the fixedpre-stretched electro-active polymer film is configured to: a) apply apressure to the solid body in a first condition and b) relieve thepressure in a second condition,  wherein the first condition is prior toa current being applied to the at least one stretchable conductor andwherein the second condition is after the current being applied to theat least one stretchable conductor; and c) coupling a pair of mechanicaland electrical connectors at each end of at least one active region ofthe fixed pre-stretched electro-active polymer film.
 2. The method ofclaim 1, further comprising: folding or attaching multiple layers of thepre-stretched electro-active polymer X times, wherein X is between 2 and10,000.
 3. The method of claim 1, wherein the at least one stretchableconductor is made from carbon black based solution or solvent.